Even a small solar flare can reach out and touch the Earth. On April 16th, sunspot 1190 produced a relatively minor C5-class flare. X-rays from the distant explosion broke apart molecules in Earth's upper atmosphere, creating a wave of ionization over Europe. Researcher Rob Stammes detected the sudden ionospheric disturbance or "SID" using a very low frequency radio receiver at the Polar Light Center in Lofoten, Norway:

The wave of ionization allowed signals from a terrestrial radio station to bounce over the horizon into Stamme's 23.4 kHz VLF antenna. That's what's shown in the upper panel. Now consider the lower panel: "There was also a small increase in radio noise directly from the flare itself at 56.25 MHz," points out Stammes. "Contact with the sun at VLF and VHF radio frequencies at the same moment gives me important information."

Readers, would you like to be in radio contact with the sun? Visit NASA's RadioJove web site for instructions.

It's been almost a year since NASA's Solar Dynamics Observatory began taking pictures of the sun. As the the first anniversary of First Light approaches on April 21st, researchers are taking stock of the observatory's many accomplishments. One of the most profound results turns out to be aethestic: the sun is more beautiful than anyone imaged. Consider the following extreme ultraviolet image, taken just hours ago, of the magnetic canopy of sunspot complex 1191-1193:

This stunning snapshot is actually routine material for SDO. The observatory produces a daily torrent of beauty that, even now, mission scientists haven't grown used to. Normally unflappable researchers are frequently caught staring slack-jawed at SDO movies. And when they're done, they don't have the vocabulary to describe what they have seen. Many of the phenomena SDO catches have no textbook names. SDO's starscapes may turn out to be as prized to poets, artists, and writers as they are to no-nonsense solar physicists. See for yourself.

Purdue University has created "Impact: Earth!," a website where anyone can see the simulated effects when a comet or asteroid of variable size, density, and speed hits Earth. Many people believe that asteroid and comet impacts have played a major role in the history of Earth, and Purdue has provided us with an inside look at how previous impacts might affect us today.

The Interactive website is said to be scientifically accurate enough to be used by many different branches of the government including NASA and the Department of Homeland Security.


It is also user-friendly and visual enough to be used by schools as an interactive teaching aid for elementary students. This adds a possible new and exciting way for kids to be physically hands on and learn about the earth and how impacts might affect us.

In my time watching the skies, I've seen quite a few meteors, fireballs, and bolides. The truly notable ones are few and far between, but last Saturday, I caught one that was among the most interesting I've seen. It was a slow moving, bright green one with a nice smoke trail that was easily as bright as Venus from where I saw it in the suburbs of St. Louis. I tweeted about it briefly but didn't think much more about it until I got a response from another person that saw it along with a link to a collection of observations. As nice as the observation was for me, it was nothing compared to the view some others got.

Heading over to the American Meteor Society page for a meteor around this time, it looks like a meteor matching the one I saw generated a pretty good number of reports from across the country. Several have reactions similar to my initial one: This must be a firework. Many reports confirm the smoke trail and fragmentation as well. But the reports that are really fantastic are the ones from Canada.

Amateur astronomers across the world have fallen for a cheeky asteroid that passed the Earth on Monday night.

Asteroid 2011 GP59 was caught winking at our planet from a distance away barely 10 times that of the moon.

The "winking" bit which is getting spacefans so hot and bothered stems from the fact that the asteroid is cigar-shaped and spinning madly end-to-end, comparatively speaking.

"Usually, when we see an asteroid strobe on and off like that, it means that the body is elongated and we are viewing it broadside along its long axis first, and then on its narrow end as it rotates," said Don Yeomans, manager of NASA's Near-Earth Object Program Office at the Jet Propulsion Laboratory in Pasadena, California.

"GP59 is approximately 50m long, and we think its period of rotation is about seven-and-a-half minutes.

"This makes the object's brightness change every four minutes or so."

Everyone in the south-west yesterday had their own big bang theory.

Was it an earthquake? Did Tower Hill erupt into action? Did a meteor shower crash to earth, or was it an alien invasion?

The "big bang" was heard about 1am yesterday, with reports of an "explosion" shaking homes in Winslow, Warrnambool and Terang.

"The whole house shook and there was an almighty noise, like a roar," one Warrnambool resident said yesterday.

"It had my curtains moving and set my car alarm off."

The noise was said to be accompanied by flashes of light that were variously described as being pink, orange and yellow, and seen as far away as Mortlake and Heywood.

Perry Vlahos, media liaison for the Astronomical Society of Victoria (ASV), said it was likely that the bang and the flashes of light were caused by a meteor.

"It was most likely a meteor exploding in the atmosphere," Mr Vlahos said.

"(The sound) could be a sonic boom or (a meteor) coming through the atmosphere and exploding. Even though these flashes or sound appear close, it might be quite a distance above our head."

Don Ward, an ASV member from Gorae West, said the cloudy conditions would have made it difficult to spot a meteor.

Published in the September 1999 issue of Universe.

As we approach the end of the Second Millennium, a review of ancient history is not what you would normally expect to read in the pages of Universe. Indeed, except for reflecting on the AD 837 apparition of Halley's Comet (when it should have been as bright as Venus and would have moved through 60 degrees of sky in one day as it passed just 0.03 AU from Earth - three times closer than Hyakutake in 1996), you may well wonder what we could learn from any astronomical events that occurred more than a thousand years ago.

Any history text will say that the Dark Ages refers to the period after the fall of the Roman Empire in the middle of the 1st Millennium (it was not sponsored by the International Dark Sky Association). It was a time when European civilisation stagnated - even that term is a generous description of the living standards and social setting of the next few centuries. In a broader sense, however, "Dark Ages" can be applied to a few eras of social upheaval over the last several thousand years, which fits in nicely with what you're about to read - stay with me, as the possible astronomical implications will soon become apparent.

Physical Aspects Of The Dark Ages

Let's first look at the onset of "the" Dark Ages in the sixth century AD. The Roman Empire was finished, nothing was happening in the sciences, and worse was happening in nature. The Italian historian Flavius Cassiodorus wrote about conditions that he experienced during the year AD 536:

"The Sun...seems to have lost its wonted light, and appears of a bluish colour. We marvel to see no shadows of our bodies at noon, to feel the mighty vigour of the Sun's heat wasted into feebleness, and the phenomena which accompany an eclipse prolonged through almost a whole year. We have had a summer without heat. The crops have been chilled by north winds, [and] the rain is denied."

Other writers of the time described similar conditions:

Procopius : "...during this year a most dread portent took place. For the Sun gave forth its light without brightness...and it seemed exceedingly like the Sun in eclipse, for the beams it shed were not clear."

Lydus : "The Sun became dim...for nearly the whole year...so that the fruits were killed at an unseasonable time."

Michael the Syrian : "The Sun became dark and its darkness lasted for eighteen months. Each day it shone for about four hours, and still this light was only a feeble shadow...the fruits did not ripen and the wine tasted like sour grapes."

Was this a local phenomenon? According to the book Volcanoes of the World, Dr. Timothy Bratton has noted that there was a small eruption of the volcano Mt. Vesuvius in AD 536. Could this be the cause? It may well have contributed to the scene (although the eruption was much smaller than the big one of AD 79), but it can not really account for the similar conditions that were experienced around the world.

In China, "the stars were lost from view for three months". Records indicate that the light from the Sun dimmed, the expected rains did not eventuate, and snow was seen in the middle of summer. Famine was widespread, and in the midst of the turmoil, the Emperor abandoned the capital.

Calaveras County Sheriff's Detectives are investigating a loud explosive sound that was reported in several communities yesterday.

According to the Sheriff's Office, at around 8:50 am, the Sheriff's dispatch received multiple 9-11 calls from San Andreas, Mokelumne Hill, Mountain Ranch, Railroad Flat and West Point. All of the callers said that heard a single loud explosion type noise, but there were no reports of fire or smoke being seen and no specific location given.

Several callers also stated that a plane had flown overhead just prior to the loud explosion and they suspected it was a sonic boom. Sheriff's Dispatch checked with the FAA and Calaveras County Airport who had no reported planes in distress in the area.

The Sheriff's Office will also follow-up with local military contacts in an attempt to confirm the possible sonic boom that was heard by many county residents.

A G1-class geomagnetic storm is in progress, sparked by a high-speed solar wind stream which is buffeting Earth's magnetic field. High latitude sky watchers should be alert for auroras.

Shawn Malone sends this picture, taken before sunrise on April 12th, from Marquette, Michigan:

"I coaxed myself out of bed around 4am and was rewarded by a lightshow!" says Malone. "The auroras had no problem shining through the light pollution. I think the sun IS waking up. I watched the Northern Lights until the sunlight wiped them out."

A magnificent filament of magnetism is curling around the sun's southeastern quadrant today. Measuring more than 700,000 km from end to end, the vast structure is about twice as long as the separation between Earth and the Moon. Arrows trace the filament's meandering path in this extreme UV image from NASA's Solar Dynamics Observatory:

It's not easy for such a filament to remain suspended indefinitely above the stellar surface, and indeed a collapse is possible. Filaments falling onto the sun can trigger explosions called "Hyder flares." Is one in the offing? Readers with solar telescopes are encouraged to monitor developments.